This invention relates generally to pumps and more particularly to a check valve for a pump. Many types of pumps use check valves; however for the purpose of describing the present invention diaphragm pumps in particular are considered herein. Typical diaphragm pumps use an elastomeric component as a passive check valve to facilitate the pumping action of the pump. A pump will typically contain two valves, one identified as the inlet valve and the other identified as the outlet valve. During the down-stroke or intake stroke of the pump, the suction action of the diaphragm will pull the inlet valve into an open position and the outlet valve into a closed position thus pulling the media into the pump on the inlet side only. During the up-stroke or exhaust stroke of the pump, the compression action of the diaphragm will push the inlet valve into a closed position and the outlet valve into an open position thus expelling the media on the outlet side only.
The valves will perform this action once during each cycle of the pump. For a diaphragm pump, this equates to once per full revolution. Therefore, a diaphragm pump that runs at 4000 RPM will cycle the valves 67 times per second. The speed of the pump, multiplied by the volume the pump displaces with each stroke determines how much force is applied to actuate the valve, thus directly impacting how far the valve will displace if not physically limited. If this valve travel distance is not controlled correctly, the valve can easily travel further than required or could also be over-restricted and not allowed to travel as far as needed. Either condition results in a pump that runs inefficiently and/or produces higher than desired noise levels.
Accordingly, there is a need for a pump valve having a controlled stroke.